Help with PC Power Issues - Troubleshooting Needed

[NewkyBroon]

Hi everyone,

I'm having a frustrating issue with my PC that I could use some help troubleshooting.

A couple of weeks ago, I powered off my PC and when I tried to start it up the next morning, it wouldn't boot properly. The system powers up for a couple of seconds, but then shuts itself down almost immediately.

At first, I thought it was a faulty PSU, so I decided to upgrade my system as I was already looking at this. However, when I plugged in the new PC last week, the same thing happened. This led me to believe the issue might be with the wall socket or the home's electrical system (since I live in an older house).

A few details:

• I have a surge protector, but I can’t recall if the old PC was plugged into it or directly into the wall before the issue occurred. I do know it has been working fine from that same socket for the past year.
• For the new PC, I mistakenly plugged it directly into the wall (not the surge protector) when first starting it.
• With the old PC, I had upgraded from a 3080 to a 4070 TI GPU a few days before the issue started, but everything ran fine for a few days before the issue presented itself.
• I’ve done some basic troubleshooting on both systems (resetting the motherboard, removing RAM), and I tested the voltage of the wall socket with a multimeter. It's reading 240V (live/neutral and live/earth), so the socket seems fine (???).
• Despite the issues with the PC, the same socket is still powering a router and I also tested a floor light on it, and everything is working fine there.
• I tried plugging the new PC into a separate socket in the house, but the issue persists (this was after plugging it in to the "potentially" dodgy wall socket mentioned above, had some damage already been done?).

For context, the socket I'm using is a double socket. One side has an 8-plug surge protector that powers the PC, two monitors, a router, and a 2-speaker sound system.

Before I try plugging in my replacement PC (which arrived yesterday), any advice on what I should check or do next? I’m stumped and could really use some guidance.

Thanks in advance for your help!